It is well-known that certain microorganisms will grow only in atmospheres that are substantially oxygen-free. Therefore, when such microorganisms are to be identified for diagnostic purposes or are to be transported or stored, it is necessary that they be maintained under anaerobic or substantially oxygen-free conditions. There are various techniques described in the prior art for obtaining such anaerobic conditions. One procedure is to evacuate the container for the microorganisms and thus eliminate any oxygen-containing atmosphere. This requires undesirable evacuation apparatus. U.S. Pat. No. 3,246,959 discloses apparatus for maintaining an anaerobic environment within a closed container. U.S. Pat. Nos. 3,616,263; 3,773,035; 3,913,564; 3,961,696; 4,012,203; 4,014,748; 4,038,148; 4,082,614 and 4,108,728 also disclose apparatus for obtaining an anaerobic environment in apparatus for storing and/or transporting microorganisms. These prior art apparatus contain oxygen-free gas, such as carbon dioxide, in pressurized containers to be released when desired or they employ compositions and catalysts to generate reducing gases which then react with oxygen to provide an oxygen-free environment or an environment wherein the oxygen content is reduced to a point where it is not harmful to the microorganisms being employed therewith. While these prior art apparatus are all capable of providing an anaerobic environment, there is still a need for a convenient apparatus for generating such anaerobic environment.